A quantitative review of marine mortality and an investigation into the effect of migration on sockeye salmon (Oncorhynchus nerka)

Marine mortality has remained a poorly understood component of Pacific salmon life-history indicating a need for the re-evaluation of research practices. 45 peer-reviewed journals were retrieved from 1965 to 2010 that addressed the topic of survivorship of sockeye salmon (Onchorhynchus nerka) during the marine phase of migration. To accurately describe the historical trends in research, four topics were quantified in the review: (1) the geographic location of the study, (2) the marine life stage, (3) the type of research question, and (4) the sampling level. Regional trends over the entire time series indicated British Columbia produced the most research followed closely by Alaska, Washington and Oregon, Russia and Japan. Research on the sub-adult and estuarine life stages were significantly less abundant in the literature compared to those that examined adults and coastal-migrating juveniles. All articles in the search (100%) addressed population characteristics. Morphological/physiological, abiotic, and biotic research questions were close to equally addressed in more than 50% of articles, while only 22% of articles examined abiotic factors. Most articles relied solely on population based sampling or individual based sampling with few choosing to incorporate both methods into methodology. Only 9 articles returned in the search used telemetry. Recommendations for future research include an increased attention to anthropogenic factors and pathogens affecting marine mortality, an emphasis on international collaboration, and the shifting population research toward an interdisciplinary approach as proposed in Cooke, Hinch et al. (2008).Forestry, Faculty ofForest Sciences, Department ofUnreviewedUndergraduat